45-year-old man with left-upper-quadrant abdominal pain

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Ruptured intracystic pseudoaneurysm of the left gastric artery, which complicated pancreatitis

Findings

An initial noncontrast CT of the abdomen revealed a 9.9 × 6.0-cm
hemorrhagic mass of the pancreatic body (Figure 1). A subsequent
contrast-enhanced CT showed a 2.4-cm ruptured pseudoaneurysm of the left
gastric artery within a large pancreatic pseudocyst (Figure 2). The
patient was transferred to our hospital for endovascular treatment of
his pseudoaneurysm. The left gastric artery was selectively injected and
exhibited a leaking pseudoaneurysm (Figure 3).

Discussion

A visceral pseudoaneurysm is a serious complication of pancreatitis that occurs angiographically in up to 10% of the cases.1 The
pathophysiology is proposed to be autodigestion of the peripancreatic
arterial wall secondary to released proteolytic enzymes or erosion of a
pseudocyst into the artery and conversion of its cavity into a
pseudoaneurysm. The most commonly involved vessels include the splenic,
gastroduodenal, and pancreaticoduodenal, which account for up to 90% of
total pseudoaneurysm involvement.2 Involvement of the left gastric artery is very unusual, with only 5 cases published in the literature.2-5 Dahan et al4 described
successful left gastric artery coil embolization of a ruptured
pseudoaneurysm in 1997. The left gastric artery is rarely involved
because of its cephalad position with relation to the pancreas. Our
patient had a large 9.9-cm pseudocyst extending cephalad from the body
of the pancreas, which extended into and abutted the left gastric
artery. Subsequent arterial wall degradation led to pseudoaneurysm
formation and rupture. Fortunately, the pseudoaneurysm was intracystic,
which acted to partially tamponade the aneurysm rupture. Pseudo-aneurysm
rupture in association with a pseudocyst, as in our case, is reported
in 15% to 20% of cases.2 Recognition of this rare
complication is extremely important; it has a reported mortality rate of
up to 29% with treatment and up to 90% without treatment.6 Unusual
complications have been described secondary to left gastric
pseudoaneurysms, including hemosuccus pancreaticus (hemoductal
pancreatitis) and wirsungorrhagia (direct pseudoaneurysm rupture into
the duct of Wirsung).4,5 CT, angiography, and ultrasound have
all been successful in the identiﬁcation of the pseudoaneurysm and are
acceptable diagnostic modalities. Both surgery and endovascular
embolization have traditionally been proposed for treatment. Management
of pseudo-aneurysms related to pancreatitis is essential because of the
high mortality rate without treatment as described above.1,6,7 Surgical
treatment of pseudoaneurysms is initially successful in 70% to 85% of
cases but is also associated with mortality rates of 20% to 25%.8 There is a lower mortality rate of 16% reported if the pseudoaneurysm is in the body or tail of the pancreas.8 Percutaneous
embolotherapy has a higher reported initial success rate of between 78%
and 100% and a lower overall mortality rate of up to 16%.2,9-11 Recurrent hemorrhage with embolotherapy has been reported in up to 37% of cases.2 Catheter
embolization options for peripancreatic pseudoaneurysms include
metallic coils (as in our case), cyanoacrylate glue, gelatin sponge,
interlocking detachable coils, ethiodized oil, particles of dura mater,
vasopressin, and 2,10,12,13 Direct percutaneous embolization
with metallic coils or thrombin under ﬂuoroscopic guidance was also
proposed as a viable alternative by Araoz et al14 and Luchs et al.15 The
most common technique reported uses a combination of metallic coils and
a gelatin sponge. The only major embolic complication described in
multiple studies was distal embolization of glue with resultant partial
duodenal and partial splenic infarction.2,10 Both the
surgical and endovascular literature proposes initial embolization in
pancreatic head pseudoaneurysms, with subsequent surgical intervention,
if necessary and possible, in the case of recurrent hemorrhage. Initial
management of pseudoaneurysms adjacent to the pancreatic body and tail
in surgical candidates is still controversial because of the relatively
lower mortality rate in this region; such patients should be managed on a
case-by-case basis.

Conclusion

Left gastric artery pseudoaneurysm is a rare but serious complication
of pancreatitis. Only 5 cases were found in the literature. Although
rare, vessels need to be followed and examined closely in pancreatitis
and especially in pancreatic pseudocysts to make this potentially
lifesaving diagnosis. Endovascular coiling is a minimally invasive and
effective alternative to surgical intervention.